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OPERATION AND MAINTENANCE AT SAFARI-1 RESEARCH REACTOR IN
SOUTH AFRICA
Date
Presented By:
Dr DL Tillwick
Consultant
(Past Senior Manager: SAFARI-1)
Acknowledgement to co-writers: Mr AJ D’ Arcy and Mr JF du Bruyn
4
Role of SAFARI-1
20 MW Research Reactor
Operational since March 1965 (46 Years)
90% Funded by NTP commercial sales
NTP also funds:
o LEU fuel element final disposal, and
o D&D of SAFARI-1 from April 2010
10% Funded by Necsa for historical liabilities
Reactor needed until early 2020s for commercial production
With operation of Dedicated Isotope Production Reactor (DIPR) in early
2020s SAFARI-1 will function as back up and focus on R&D
HEU to LEU conversion of fuel completed and 99Mo target plate licensed
SAFARI-1 Operation
6
The era of production in the reactor is reflected in the increased usage below:
Reactor maintenance scheduled down time per annum is currently:
o Ten 5 day shutdowns with 21 to 35 days operating cycle
o One 12 day shutdown
o Total scheduled shutdown time is ~62 days with 303 days operation
at full power
SAFARI-1 Operational Performance
7
Year 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Operational
time (Days)
317.0 310.1 314.2 308.0 312.5 290.9 298.2 304.8 300.9 306.7 ~306
Scheduled
downtime
45.4 53.3 49.0 53.3 50.6 55.4 55.0 55.5 62.5 62.5 62.5
Unschedule
d downtime
2.6 1.5 1.8 4.7 1.8 18.7 11.3 4.8 1.5 0.2 0.1
0
50
100
150
200
250
300
350Ti
me
in D
ays
Year
SAFARI-1 Operational Availability (Days)
Operational time (Days) Scheduled downtime Unscheduled downtime
Maintenance Programmes
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The maintenance programmes list:
o Responsibilities for tasks
o Frequency of maintenance i.e. daily, weekly, monthly, yearly and >1 year
o Schedule of tasks
o Criteria and controls for maintenance tasks
o Systems which can be isolated when reactor is in operation
o Applicable restrictions for on-line maintenance
o Records to be kept
The maintenance programmes cover the following:
o Routine tasks ~1919 per annum
o Shutdown tasks ~572 per annum
o Ad hoc tasks ~434 per annum
Maintenance Control
9
Included in maintenance programmes are the following verification controls:
o Operational checks
o Functional tests
o Periodic routine inspections
o In-service inspections
All maintenance instructions and tasks comply with the Operating Technical
Specification (OTS) and requirements of the Safety Analysis Report.
System, Structures and Components (SSC) depending on safety classification
are subject to the following controls prior to installation:
o Design and procurement control
o Manufacturing control in SAFARI-1 workshop and
in Necsa ASME VIII and ASME III nuclear manufacturing facility
o Approval and qualification of supplier, and QC release
Continues…
Maintenance Control Continued
10
Prior to reactor shutdown a shutdown meeting is held and the
Maintenance Shutdown Programme (MSP) agreed on
The MSP is approved and forwarded to the National Nuclear Regulator
who performs regular surveillances
Maintenance tasks completed during the shutdown are reviewed w.r.t.
records and in the post shutdown meeting to ensure compliance to MSP,
OLC and OTS
For in-service inspections procedures and plans are drawn up and most are
performed as part of the MSP
11
Ageing Management System
The IAEA SSG-10 Guide provides guidance for ageing management system
for Research Reactors (RR):
Over the life of the of the RR
Establishing an ageing management system
Preventing ageing through appropriate preventative maintenance
Detecting ageing through ISI
Assessing and mitigating ageing effects by using an
Ageing Management Programme (AMP)
Promote safety culture through implementation
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Ageing Management Programme
In SAFARI-1 the AMP was integrated with the existing Integrated
Management System (IMS) but the following systems were strengthened:
Design control
Project management
Configuration management
Calculation control
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Methodology for Selecting Ageing Management Projects
Use following methodology to select and prioritise ageing management projects:
1. Determine Ageing System, Structure and Components (SSC)
2. For each Ageing SSC define the applicable Ageing Mechanisms (AM)(1 - 13)
3. For AM identify a Remedial Actions (replace, refurbish, redesign or maintain)
4. Prioritise the Remedial Action (RA) as follows:
o If RA is not performed select applicable Impact Factors (9) and rate each
0, 5 or 10 and sum for total Impact Factor
o Multiply total Impact Factor by Weighting Factor (1-10) based on
Remedial Action being controllable, implementable, viable, cost, urgency
9
[RA Priority = Ʃ Impact Factor (0, 5 or 10) x Weighting Factor (1 to 10)] i=1
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Grouping of Ageing Systems, Structures and Components
Reactor block, fuel and internals
Cooling systems
Confinement and containment
Instrumentation and controls
Power supply
Auxiliaries (e.g. fire protection, crane, hot cells and radioactive waste handling)
Experimental facilities
Non SSC:
o Documentation (e.g. SAR, OTS and management systems)
o Staff training
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Ageing Mechanisms
Radiation resulting in changing of properties
Temperature causing changes of properties
Creep due to stress or pressure
Mechanical displacement, fatigue or wear from vibration and cyclic loads
Corrosion
Material deposition (e.g. Crud)
Flow induced erosion (e.g. orifice and concrete)
Obsolescence through technology change
Damage due to power excursions and operational events
Flooding causing deposition and chemical contamination
Fire resulting in effects of heat, smoke and reactive gases
Changes in requirements such as legislation or acceptable standards
Other time dependent phenomena
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Prioritisation of Be Reflector Elements
For Be elements 4 Ageing Mechanisms: radiation change in properties, creep due
to stress/pressure, mechanical displacement and damage due to operational events
For priority assessment four Impact Factors were identified and rated:
o Non-availability 10
o Reportable nuclear event 0
o Radiological exposure 0
o Injury to anyone 0
o Environmental releases 0
o License complications 5
o Lifetime limitations 10
o Public non-acceptance 0
o Stakeholder non-acceptance 5 (Sum of Impact Factor = 30
Weighting Factor given as 8 since Be replacement is easy, albeit at high cost
Total priority for a Remedial action to replace Be elements is 30 x 8 = 240
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Remedial Action Description Priority
Safety Critical Ageing Management
Upgrade safety-critical neutron and gamma detectors and instrumentation 400
Safety-critical instrumentation segregation and separation of routing 280
Periodic safety review (10 yearly) and possible INSARR by IAEA 200
Mission (Operation)- Critical Ageing Management
Upgrade ventilation stack monitors and data transmission 400
Convert LEU targets 350
Replace Be reflector elements 240
Lifetime Extension Ageing Management
Asses reactor vessel lifetime for recommendation of surveillance/replacement 400
Assess reactor building and stack integrity for lifetime extension of facility 350
Organisational (Management Control) Ageing Management
Controlled storage areas for critical spares, handling tools, maintenance equip 300
Develop expertise by filling vacancies and training of personnel 240
IMS compliant to standards ISO, OHSAS, NNR, Necsa SHEQ and IAEA 150
SAFARI-1 Integrated Management System
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The Integrated Management System (IMS) integrates Quality, Health, Safety and
Environmental (QHSE), Security and Safeguards management systems and has
evolved as follows:
o From ANSI NQA-1 used in the PWR fuel manufacturing plant
o Number of PWR staff appointed by SAFARI-1 implemented system since 1994
o NNR, IAEA and Necsa SHEQ system evolved and requirements incorporated
o ISO-9001 certified in 1998
o ISO-14001 certified in 2003
o OHSAS 18001 certified in 2011
Compliance through audits show a decreasing number of findings and observations:
o Audits by NNR, Necsa SHEQ department (compliance increased by
10% to 91.8% in 2010) and Necsa Internal Audit function
o SAFARI-1 management team of 6 performed self assessment audit
Safety Management System Performance
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Nuclear safety performance - reactor scrams halved to ~10 from previous year
Excellent occupational and health record improved by means of a
Behaviour Based Safety (BBS) programme:
o Every person is trained for safety observations (~ 10 min once per month)
o One page check list used
o Personnel observed notified at start and given feedback of safe and
unsafe behaviour
o “no-name and no-blame”
o Total injury rate (annual average monthly injuries x 200 000/ possible
annual man hours) dropped to zero
21
SAFARI-1 is located within the Necsa security arrangement
Separate security fence was installed
Hardening of perimeter doors
Installation of building camera system
Biometric (throughout building) and parcel scanner
Further hardening of building inner protection areas for conformance
to INFCIRC/225/Rev.5
Security Upgrades
22
SAFARI-1 complied with and promotes international safeguards
Initially had IAEA INFCIRC/66/Rev.2. type safeguards agreement
SA signed NPT and CSA in 1991 and AP in 2002
In 2011 SA received the IAEA broader conclusion
Integrated Safeguards (IS) approach being developed
IS will use power monitor and new spent fuel storage
SAFARI-1 fuel converted from HEU to LEU in 2009
99Mo production from LEU target licensed in 2010
HEU spent fuel of US origin returned to US
Safeguards Performance
Conclusion
23
SAFARI-1 has shown reliable operation in particular during the 99Mo supply
crises in 2010 when two major producers were off line for repairs
The operational performance can be ascribed to the well developed and
implemented maintenance programme and in service inspection
For lifetime extension SAFARI-1 is actively implementing an ageing
management programme to extend its life to 2030
Nuclear safety and occupational health and safety have shown marked
improvements through BBS, active management involvement and promotion of
safety culture
The basis for the excellent performance has been a well developed IMS which is
continually being improved
SAFARI-1 which is supporting R&D activities in Necsa and SA, has become a
strategic supplier of irradiation services to NTP who technically fully funds it
from commercial sales.